<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <title>11_margin的注意事项1</title>
    <style>
        .outer {
            width: 400px;
            height: 400px;
            padding: 50px;
            background-color: gray;
        }
        .inner {
            width: 100px;
            height: 100px;
            margin: 100px;
            background-color: orange;
        }
    </style>
</head>
<body>
    <!-- 子元素的margin是参考父元素的content计算的。 -->
    <div class="outer">
        <div class="inner"></div>
    </div>
</body>
</html>